Field of the Invention
The present invention relates to photosensitive compositions, more particularly to photosensitive compositions for producing semiconductors prepared by adding a photosensitizing organic compound to a solution of a photosensitive high polymer.
The photosensitive composition to be used in the manufacturing processes of circuits for transistors, ICs, LSIs and super LSIs are generally called "resist", for which many kinds of compositions are known.
These compositions exhibit their desired functions through the successive processes including application on a substrate, exposure, development and etching. Therefore photosensitive compositions have to be possessed on the following properties:
(1) high resolution, PA0 (2) high sensitivity, PA0 (3) easy application to form a uniform coating film, PA0 (4) high corrosion resistance, and PA0 (5) high stability during storage. PA0 (1) Compound of benzoic acid family such as p-methoxybenzoic acid and p-amyloxybenzoic acid, PA0 (2) compounds of anthraquinone family such as anthraquinone and 3-chloroanthraquinone, PA0 (3) aromatic nitro compounds such as 5-nitroacenaphthene, PA0 (4) alicyclic amino compounds such as hexane diamine, N-methylcyclohexylamine and dicyclohexylamine, PA0 (5) aniline homologues such as aniline, acetanilide, o-toluidine, m-toluidine, p-toluidine, anthranilic acid, p-phenetidine, o-nitroaniline, m-nitroaniline, p-nitroaniline, o-anisidine, m-anisidine, p-anisidine, and chloroaniline, PA0 (6) N-alkylanilines such as methylaniline, dimethylaniline, ethylaniline, Michler's ketone, dimethylaminoazobenzene, p-dimethylaminobenzoic acid and p-dimethylaminobenzaldehyde, PA0 (7) arylamines such as diphenylamine, p-aminodiphenylamine and triphenylamine, PA0 (8) amines having an amino group on their side chain such as benzylamine and .beta.-phenylethylamine, PA0 (9) aromatic diamines such as o-phenylenediamine, m-phenylenediamine, p-phenylenediamine and p-aminoacetanilide, PA0 (10) condensed ring amino compounds such as naphthylamine, PA0 (11) heterocyclic compounds such as pyrrole, imidazole, N-vinylcarbazole and polyvinylpyridine, and PA0 (12) heterocyclic amines such as pyridoxamine.
In addition, stability against such reactive gases as CF.sub.4 and CCl.sub.4 and reactive gas mixtures containing those gases or in other words "high resistance against dry etching" has been more and more required in recent years, particularly for the miroprocessing. As the base polymer for producing photosensitive compositions which can meet these severe requirements, many experimental results show that polymers containing aromatic or hereto rings in their structure are most prospective and some of them have already been used for practical purposes.
Recently, the improved throughput is required from the economical point of view in the production of semiconductors. Taking resists for instance, further improvement in the sensitivity is required while such properties as resolution, applicability, corrosion resistance, storage stability and dry etching resistance are maintained or improved to higher levels. However, the photosensitive compositions so far conventionally known are not sensitive enough to satisfy the requirement of economical operation for producing semiconductors.
In their intensive investigations to improve the situation, the present inventors have succeeded in achieving remarkable improvements in the sensitivity of photosensitive compositions, while other properties, such as gamma value, are either maintained or improved, by adding an additive which is soluble in an organic solvent to a solution of a photosensitive high polymer in an organic solvent, the high polymer having in the structure an aromatic ring or a heterocyclic ring which is substituted by a group or groups containing a halogen atom or atoms. The present invention has been completed on this discovery.